Tone generator circuit for electric or electronic musical instruments

ABSTRACT

A tone generator circuit for electric or electronic musical instruments, having a band-pass filter circuit inserted in a transmission line for transmitting an electric sound from an electric sound source to a speaker and knobs for adjusting the upper and lower cutoff frequencies of the band-pass filter circuit, the knobs being slidably mounted on a guide member in such a manner that either one of them may always lie on a predetermined side of the other.

United States Patent [191 11] 3,821,461 Mieda 1 ,1une 28, 1974 [54] TONE GENERATOR CIRCUIT FOR 2,141,231 12/1938 Trautwein 84/1.l2 ELECTRIC 0 ELECTRONIC MUSICAL 2,482,548 9/1949 Kerkhof 84/D1G. 9 2,725,534 11/1955 Hemphill 333/70 R INSTRUMENTS 3,296,464 1/1967 Brault 333/70 R [75] Inventor: Fumio Mieda, Saitama, Japan 3,296,546 1/1967 Schneider 333/70 R 3,421,121 1/1969 Burnsweig et al 333/70 R [731 Ass'gneei 1? 8 9 3,462,563 8/1969 Henderson 200/47 x Kabushlkikaishlya, Tokyo, Japan [22] Filed: Dec. 26, 1972 Primary Examiner--Richard B. Wilkinson Assistant ExaminerU. Weldon [21] Appl' 3l868l Attorney, Agent, or FirmMarshall & Yeasting Related US. Application Data v V W W [63] Continuation of Ser. No. 162,978, July 15, 1971, nsiqned- .3 6 V .7 r s [57] ABSTRACT [30] Foreign Application Priority Data A tone generator circuit for electric or electronic mu- July 30' 1970 Japan ..45-74717 [U] Sical instruments having a band-Pass filter Circuit serted in a transmission line for transmitting an elec- [52] US. Cl 84/ 1.19, 84/1.11, 84/DIG, 9 tric sound from an electric sound source to a speaker [51] Int. Cl. GlOh l/OZ n n s for adjusting the upper and lower cutoff [58] Field of Search 84/ 1.12, 1.11, 1,01, 1.21, frequencies of e band-pass fi t u e nobs 84/1,24, 1,18, DIG, 9, 1,19; 333/70 R; 200/47 being slidably mounted on a guide member in such a manner that either one of them may always lie on a [56] 7 References Cited predetermined side of the other.

UNITED STATES PATENTS 1,735,742 11/1929 Fetter 333/70 R 1,916,187 6/1933 Read 84/1.21 2 Clams 3 Drawmg Fgures This is a continuation of application Ser. No. 162,978, filed July 15, 1971 now abandoned.

BACKGROUND or THE INVENTION 1. Field of the Invention This invention relates to a tone generator circuit for electric or electronic musical instruments, and more particularly to a tone generator circuit for electric or electronic musical instruments which is capable of providing musical sounds of various tones.

2. Description of the Prior Art In conventional types of tone generator circuits for electric or electronic musical instruments an electric sound derived from an electric sound source is only supplied to a speaker through an amplifier. No attempt has been made for producing musical sounds of various tones by altering the frequency characteristic of the amplifier. Therefore, the prior tone generator circuits produce a musical sound of one particular tone dependent upon the frequency characteristic of the amplifier used.

SUMMARY OF THE INVENTION The primary object of this invention is to provide a tone generator circuit for electric or electronic musical instruments which is adapted for selective production of musical sounds of many different tones similar to, for example, those of a brass, a violin, a pipe organ and so on.

Another object of this invention is to provide a tone generator circuit for electric or electronic musical instruments which is designed to produce a vibrato effect, a shoot effectand so on.

Other objects, features and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1 and 2 are connectiondiagrams illustrating examples of a tone generator circuit for electric or electronic musical instruments respectively produced according to this invention. I

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 reference numeral 1 indicates an electric sound source in electric or electronic musical instruments. A sound signal derived from the electric sound source 1 is fed to a high-pass filter 2, the output of which is supplied to a low-pass filter 4, if necessary, through a buffer amplifier 3 and the output of the filter 4 is applied to a speaker 6 through a main amplifier 5.

The high-pass filter 2 is made up of a series circuit A of a plurality of capacitors C1 and C and a change-over switch B having fixed contacts S, to 8,, and a movable contact 8,. One end of the series circuit A- is connected to an input terminal 20 of the filter 2, if necessary, through a resistor 7, the contacts 8,, S are connected between the capacitors C and C between C and C (the contact S, is connected to the other end of the capacitor C, of the series circuit A), the movable contact S is connected to an output terminal 2b of the filter 2 and a suitable impedance element, for example, an inductor 8 is connected between the output. terminal 212 and ground. While, the low-pass filter 4 consists of a series circuit A of a plurality of capacitors C to C and a change-over switch B having fixed contacts 8, to S and a movable contact 8,. One end of the series circuit A is connected to an input terminal'4a of the filter 4, if necessary, through a series circuit of a suitable impedance element, for example, an inductor 9 and a resistor 10 and to an output terminal 4b of the filter 4. The contacts 8,, S are connected between the capacitors C and C between C and C respectively (the contact Sm is connected to the other end of the capacitor C,,, of the series circuit A) and the movable contact 8,, is grounded. In this case, the contacts S to 8,, of the change-over switch B are stripeor leaf-shaped and sequentially arranged in a common plane in adjacent relation or over lapping but electrically insulated relation to adjacent ones. The movable contact S has a contact portion a little extending in the direction of the array of the contacts S to S or fork-shaped as illustrated in the figure in such a manner that the movable contact 8,, may always be in contact with any of the fixed contacts 8, to S The contacts 8, to S,,, of the change-over switch B are also identical in construction with those S to S A stationary guide rail 11 is provided in common to the high-pass filter 2 and the low-pass filter 4 and knobs D and D are slidably mounted on the rail 11. The knobs D and D are associated with the movable contacts S and 5,, of the change-over switches B and B through appropriate linkage means, as indicated by the broken line, respectively such that the change-over switches B and B are caused to actuate selectively the contacts S to S,, and S to S,,, in response. to the sliding movement of the knobs D and D on the rail 11. In this case, the knob D is disposed on the left of the knob D on the rail 11 and is adapted so that when the knob D (or D) is slid to right (or left), the knob D (or D) is not brought to the right (or left) of the knob D (or D) and that when the knobs D and D are slid to right respectively, thecontacts S and S slide from the side of the contacts S and S, to the side of those 8,, and S respectively.

With the above arrangement, in the high-pass filter 2 the capacitors C to C are connected in series between the input and output terminals 2a and 2b, so that sliding movement of the knob D to right (or to left) causes a decrease (or an increase) in the capacitance of the series-connected capacitors to present a high-pass characteristic in which the cutoff frequency rises (or lowers). While, in the low-pass filter 4 the capacitors are connected in series between the terminals 4a and 4b and ground, so that sliding movement of the knob D to right (or left) causes a decrease (or an increase) in the capacitance of the series-connected capacitors to provide a low-pass filter characteristic in which the cutoff frequency rises (or lowers). Accordingly, if the capacitances of the series-connected capacitors of the filters 2 and 4 are selected such that the cutoff frequency of the filter 2 may be a little lower than that of the filter 4 irrespective of the positions of the knobs D and D on the rail 11 when they are held as close to each other as possible, the high-pass and low-pass filters 2 and 4 constitute a band-pass filter circuit whose lower and upper frequencies are determined by the cutoff frequencies of the filters 2 and 4 respectively and it is possible to obtain a band-pass filter characteristic such that the pass band width and position can be changed at will. In this case, since th knob D is not ever brought to the right of the knob D, there is no possibility of the band-pass filter characteristic being lost.

With the present invention such as described in the foregoing, when the knobs D and D are brought relatively to left while being held adjacent to each other, a relatively narrow band-pass characteristic having a center frequency of, for example, about 1,000 c/s is provided to produce a tone similar to that of a brass. By bringing the knob D relatively to left and the knob D to right, a band-pass characteristic of, for example, 800 to 12,000 c/s is obtained to produce a tone similar to that of a violin. By bringing the knob D to left and the knob D relatively to right, a band-pass characteristic of, for example, 100 to 1,200 c/s is obtained to produce a tone similar to that of a pipe organ. Further, a vibrato effect can be produced by slightly moving only, for example, the knob D to the right and left and a sound effect like trumpet shoot can be obtained by simultaneously moving to right and left the knobs D and D held close to each other.

Although the foregoing description has been given in connection with the case where the knobs D and D are disposed on the common rail 11, it is also possible to provide guide rails 11 and 11 for the knobs D and D respectively as depicted in FIG. 2, in which elements corresponding to those in FIG. 1 are marked with the same reference numerals and characters and no detailed description therefor will be repeated In this case, however, the rails 11 and 11 are disposed in parallel to each other in such a manner that the knob D is not brought to the right of the knob D and the knobs D and D are adapted so that when the knob D (or D) is moved to right (or left), the knob D (or D) or an engaging member (not shown) attached thereto engages with the knob D (or D) or an engaging member (not shown) attached thereto and that when the knob D (or 12'.) is ttbs m9ys t9 i .r IE9): sb 9r D) may slide to right (or left) together with the knob D (or D). Thus, it will be seen that the same results as those in FIG. 1 can be obtained with the construction of FIG. 2.

In the foregoing the band-pass filter circuit is made up of the high-pass and low-pass filters 2 and 4 but the band-pass filter circuit may be such that which is formed of a single or a plurality of circuits and has circuits or elements capable of adjusting the upper and lower frequencies of its band-pass characteristic, in which case the knobs are associated with the adjusting circuits or elements, thereby to provide the same effects as those previously described.

It will be apparent that many mosifications and variations may be effected without departing from the scope of the novel concepts of this invention.

I claim as my invention:

1. In an electronic musical instrument, in combination, a tone generator, sound reproducing means and a filter circuit connecting the tone generator to the sound reproducing means, 'said filter circuit comprising a lowpass filter section and a high-pass filter section in series with the low-pass filter section, each of the low-pass and high-pass filter sections having switching means including a movable contact for adjusting a cutoff frequency of the section, and knobs movably supported on a stationary supporting means and mechanically linked with the movable contacts respectively, each knob constituting a movable stop to limit the travel of the other knob, whereby the adjusted cutoff frequency of the low-pass filter section is always higher than the adjusted cutoff frequency of the high-pass filter section.

2. A tone generator circuit for electric or electronic musical instruments as claimed in claim 1, wherein said stationary supporting means has a common guide rail on which are slidably mounted said upper and lower cutoff frequency adjusting knobs. 

1. In an electronic musical instrument, in combination, a tone generator, sound reproducing means and a filter circuit connecting the tone generator to the sound reproducing means, said filter circuit comprising a low-pass filter section and a high-pass filter section in series wiTh the low-pass filter section, each of the low-pass and high-pass filter sections having switching means including a movable contact for adjusting a cutoff frequency of the section, and knobs movably supported on a stationary supporting means and mechanically linked with the movable contacts respectively, each knob constituting a movable stop to limit the travel of the other knob, whereby the adjusted cutoff frequency of the low-pass filter section is always higher than the adjusted cutoff frequency of the high-pass filter section. 